The present invention relates to a fuel cell system, and more specifically, a fuel cell system having a defrosting function for defrosting component devices or the like of the system.
In a fuel cell system, water is produced on the cathode side as a result of the cell reaction in the fuel cell. Water produced in such a manner (which will be referred to as xe2x80x9cthe produced waterxe2x80x9d hereinafter) is retrieved to a tank and then circulated to be used as supply water to a reformer, in order to increase electricity-generation efficiency and decrease frequency in water supply.
Japanese patent application Laid-Open publication No.8-273689 discloses defrosting of water distributing pipes in a fuel cell system.
As a result of elaborate study by the present inventors, it has been found out that, in a fuel cell system, in a case in which the fuel cell system is applied to a vehicle such as an electric car or the like, the produced water by the cell reaction is often accumulated in the system due to its frequent switching between the operation state and the stopped state.
Since the vehicle is quite often used in a region of cold climate, it is very important that countermeasure is taken so that the ice or frost derived from the produced water is reliably defrosted.
More specifically, such countermeasure should be taken in a sufficient level not only for the water distributing pipes in a fuel cell system, but also for various devices constituting the fuel cell system.
As an example of such various component devices which require defrosting treatment is a battery for the vehicle. This is because, in the battery for the vehicle, the battery capacity during operation needs to be maintained at a predetermined value or more in order that some auxiliary devices in the vehicle such as a compressor or a pump which consume a large amount of electricity can be swiftly and surely actuated if required in a low temperature environment.
The present invention has been achieved on the analysis described above and an object thereof is to provide a fuel cell system having a defrosting function for defrosting related devices in the fuel cell system.
The fuel cell system of the present invention comprises a fuel cell, a reformer having a combustor and supplying hydrogen containing gas to the fuel cell, a first defrosting system introducing exhaustion gas from the combustor to a first group of system component devices, a compressor supplying oxygen containing gas to the fuel cell, a heater heating the oxygen containing gas from the compressor by utilizing the exhaustion gas from the combustor as a heat source, a second defrosting system introducing the oxygen containing gas heated by the heater into a gas-liquid path of a second group of system component devices, and a third defrosting system introducing the oxygen containing gas heated by the heater into the outer surface of a third group of system component devices.
In other words, the fuel cell system of the present invention comprises a fuel cell, a reforming means for supplying hydrogen containing gas to the fuel cell, the reforming means having a combustor, a first defrosting means for defrosting a first group of system component devices by introducing exhaustion gas from the combustor thereto, a compressing means for supplying oxygen containing gas to the fuel cell, a heating means for heating the oxygen containing gas from the compressing means by utilizing the exhaustion gas from the combustor as a heat source, a second defrosting means for defrosting a second group of system component devices by introducing the oxygen containing gas heated by the heating means into a gas-liquid path thereof, and a third defrosting means for defrosting a third group of system component devices by introducing the oxygen containing gas heated by the heating means into the outer surface thereof.